Bituminous froth inline steam injection processing

ABSTRACT

An inline bitumen froth steam heater system is comprised of steam injection and static mixing devices. The steam heater system heats and de-aerates an input bitumen froth without creating downstream processing problems with the bitumen froth such as emulsification or live steam entrainment. The inline bitumen froth steam heater is a multistage unit that injects and thoroughly mixes the steam with bitumen resulting in an output bitumen material having a homogenous temperature of about 190° F. The heating system conditions a superheated steam supply to obtain saturated steam at about 300° F. The saturated steam is contacted with a bitumen froth flow and mixed in a static mixer stage. The static mixers provide a surface area and rotating action that allows the injected steam to condense and transfer its heat to the bitumen froth. The mixing action and the increase in temperature of the bitumen froth results in reduction in bitumen viscosity and also allows the release of entrapped air from the bitumen froth.

FIELD OF THE INVENTION

This invention relates to bitumen processing and more particularly isrelated to heating bituminous froth using inline steam injection.

BACKGROUND TO THE INVENTION

In extracting bitumen hydrocarbons from tar sands, one extractionprocess separates bitumen from the sand ore in which it is found usingan ore washing process generally referred to as the Clark hot waterflotation method. In this process, a bitumen froth is typicallyrecovered at about 150° F. and contains residual air from the flotationprocess. Consequently, the froth produced from the Clark hot waterflotation method is usually described as aerated bitumen froth. Aeratedbitumen froth at 150° F. is difficult to work with. It has similarproperties to roofing tar. It is very viscous and does not readilyaccept heat. Traditionally, processing of aerated bitumen froth requiresthe froth to be heated to 190° to 200° F. and deaerated before it canmove to the next stage of the process.

Heretofore, the aerated bitumen froth is heated and de-aerated in largeatmospheric tanks with the bitumen fed in near the top of the vessel anddischarged onto a shed deck. The steam is injected below the shed deckand migrates upward, transferring heat and stripping air from thebitumen as they contact. The method works but much of the steam iswasted and bitumen droplets are often carried by the exiting steam anddeposited on nearby vehicles, facilities and equipment.

SUMMARY OF THE INVENTION

The invention provides an inline steam heater to supply heated steam toa bitumen froth by direct contact of the steam to the bitumen frothresulting in superior in efficiency and environmental friendliness thanprocesses heretofore employed.

In one of its aspect, the invention provides an inline bitumen frothsteam heater system including at least one steam injection stage, eachsteam injection stage followed by a mixing stage. Preferably, the mixingstage obtains a mixing action using static mixing devices, for example,using baffle partitions in a pipe. In operation, the invention heats thebitumen froth and facilitates froth deaeration by elevating the frothtemperature. In operation the bitumen froth heating is preferablyobtained without creating downstream problems such as emulsification orlive steam entrainment. The froth heater is a multistage unit thatinjects and thoroughly mixes the steam with bitumen resulting insolution at homogenous temperature. Steam heated to 300 degreesFahrenheit is injected directly into a bitumen froth flowing in apipeline where initial contact takes place. The two incompatiblesubstances are then forced through a series of static mixers, causingthe steam to contact the froth. The mixer surface area and rotatingaction of the material flowing through the static mixer breaks thecomponents up into smaller particles, increasing contact area andallowing the steam to condense and transfer its heat to the froth. Thereduction in bitumen viscosity also allows the release of entrapped air.

Other objects, features and advantages of the present invention will beapparent from the accompanying drawings, and from the detaileddescription that follows below. As will be appreciated, the invention iscapable of other and different embodiments, and its several details arecapable of modifications in various respects, all without departing fromthe invention. Accordingly, the drawings and description of thepreferred embodiments are illustrative in nature and not restrictive

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a functional block diagram of a preferred embodiment of abitumen froth heating process arrangement of the invention.

FIG. 2 is a cross section elevation view of an inline steam heater andmixer stage of FIG. 1.

FIG. 2 a is an elevation view of a baffle plate of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with a preferred embodiment of the process two inputscomponents, namely, bitumen froth and steam, are contacted to produce anoutput homogenous bitumen product heated to a temperature of 190° F. Theinput bitumen froth component 10 is supplied at about 150° F. In a pilotplant implementation the input bitumen froth component is supplied via a28 inch pipeline at a rate of about 10,000 barrels per hour. The inputsteam component 12 is supplied as a superheated steam at about 500° F.and at 150 psi.

FIG. 1 shows a functional block diagram of a preferred embodiment of abitumen froth heating apparatus arranged in accordance with theinvention. The input steam component 12 is supplied to a pressurecontrol valve 14 which reduces the pressure to a set point pressure,which is typically about 90 psi. A pressure transmitter 16 is providedto monitor the pressure of the steam downstream from the pressurecontrol valve 14 to provide a closed loop control mechanism to controlthe pressure of the steam at the set point pressure. The pressurecontrolled steam is supplied to a temperature control valve 18 that isused to control the supply of condensate 20 to cool the steam to itssaturation point, which is about 300° F. at the controlled pressure of90 psi. A temperature sensor 22 monitors the steam temperaturedownstream from the temperature control valve to provide a closed loopcontrol mechanism to control the temperature of the steam at thetemperature set point setting.

The optimum parameters for steam injection vary so a computer 24executes a compensation program to review the instantaneously suppliedinstrumentation pressure 26 and temperature 28 measurements and adjustsinlet steam pressure and temperature set point settings as required. Apressure sensor 29 measures the pressure of the input bitumen component10 to provide the compensation program executing on computer 24 withthis parameter to facilitate optimum control of the parameters for steaminjection.

To provide a greater capacity for supply or transfer of heat to thebitumen froth component, the pressure and temperature controlled steam30 is split into two steam sub-streams 30 a, 30 b. Each steam sub-streamis supplied to a respective steam injector 32 a, 32 b and the steaminjectors 32 a and 32 b are arranged in series to supply heat to thebitumen froth component stream 10. While two steam injectors arranged inseries are shown in the figure, it will be understood that the bitumenfroth component stream 10 could equally well be split into twosub-streams and each bitumen froth component sub-stream supplied to arespective steam injector arranged in parallel. Moreover, it will beunderstood that more than two sub-streams of either the steam componentor the bitumen component streams could be provided if process flow ratesrequire. A suitable inline steam injector 32 a, 32 b is manufactured byKomax Systems Inc. located in Calif., USA.

An inline steam injection heater works well in heating water compatiblefluids but bitumen is not water compatible so additional mixing isadvantageous to achieve uniform fluid temperature. Consequently, in thepreferred embodiment depicted in FIG. 1, the bitumen and steam materialflow mixture is passed through an inlet baffle 34 a, 34 b downstreamfrom the respective steam injector 32 a, 32 b. The inlet baffle, whichis shown more clearly in FIG. 2 a, directs the material flow mixturedownward to initiate the mixing action of the steam component with thebitumen froth component. Mixing of the material flow continues bypassing the material flow through static mixers 36 a and 36 brespectively.

As seen most clearly in FIG. 2, the static mixers provide baffles 40arranged along the interior volume of each static mixer to effect amixing action of the material flowing through the static mixer. Themixing action of the material flow through the static mixer is providedby arranging the baffles 40 within the static mixer to impart a lateral,radial, tangential and/or circumferential directional component to thematerial flow that changes repeatedly along the length of the staticmixer. Different static mixer designs and baffle arrangements may beused to advantage in mixing the steam component with the bitumen frothcomponent.

A temperature transmitter 42 is located downstream of the mixers 36. Thetemperature of the material flow exiting the static mixer is measured bythe temperature transmitter 42 and is used to control the rate of supplyof steam to the inline steam injector 32 by the associated flow controlvalve 44. In this manner, a closed loop control system is provided tocontrol the supply of the steam component to the bitumen froth componentto obtain a set point or target output temperature of the material flowleaving the static mixer 36.

Referring again to FIG. 1, the heating system shown in FIG. 2 isarranged with a temperature transmitter 42 a, 42 b located downstream ofeach respective mixer 36 a, 36 b. The temperature of the materialexiting each static mixer is measured by the temperature transmitter andis used to control the rate of supply of steam to the inline steaminjectors 32 a, 32 b by the associated flow control valve 44 a, 44 brespectively. In this manner, a closed loop control system is providedto control the supply of the steam component to the bitumen frothcomponent to obtain a set point or target output temperature of thematerial flow leaving each static mixer stage 36 a, 36 b. The watercontent of the bitumen froth component 10 can range form 30% to 50%. Ina pilot plant implementation of the preferred embodiment, each inlinesteam heater 32 a, 32 b was found to be capable of heating about 10,000barrels per hour of bitumen froth by about 30° F. utilizing about 80,000pounds per hour of steam. By way of comparison to conventional processapparatus, the atmospheric tank method would use about 125,000 pounds ofsteam to achieve a similar heat transfer.

After heating, the heated bitumen froth is delivered to a plant forprocessing. To facilitate material flow rate co-ordination with theprocessing plant, the heated bitumen froth may be discharged to adownstream holding tank 46, preferably above the liquid level 48. Theheated, mixed bitumen froth releases entrained air, preferably,therefore, the holding tank is provided with a vent 50 to disperse theentrapped air released from the bitumen froth. To maintain thetemperature of the heated bitumen froth in the holding tank 46, a pump50 and recycle line 52 are provided, which operate to recycle the hotbitumen froth from the holding tank to the process inlet of the heaters.

The invention has been described with reference to preferredembodiments. Those skilled in the art will perceive improvements,changes, and modifications. The scope of the invention including suchimprovements, changes and modifications is defined by the appendedclaims.

1. Apparatus to heat a bitumen froth by steam comprising: i. a source ofsteam; ii. an inline heater body forming a bitumen inlet, a steam inletin communication with the source of steam and a mixture outlet all incommon communication with each other; iii. a baffle disposed across themixture outlet; and iv. an elongate static mixer body forming apassageway therethrough, one end of the passageway in communication withthe mixture outlet, the body supporting a plurality of baffles disposedto effect a mixing action of material flowing through the passagewaythereof.
 2. The apparatus of claim 1 wherein the baffles are disposedwithin the static mixer body to impart a lateral, radial, tangential orcircumferential directional component to a material flow through saidstatic mixer passageway that changes repeatedly along the length of thepassageway.
 3. The apparatus of claim 1 further including a steam flowcontrol valve to control the rate of steam supply to the steam inlet. 4.The apparatus of claim 3 further including a temperature transmitterdisposed to measure the temperature of material flowing through thepassageway of the static mixer forming a closed loop control system ofthe steam flow control valve responsive to the measured temperature. 5.The apparatus of claim 1 further including a steam flow pressure controlvalve to control the pressure of steam supply to the steam inlet fromthe steam source.
 6. The apparatus of claim 5 further including apressure transmitter disposed to measure the pressure of steam supplyfrom the pressure control valve forming a closed loop control system ofthe steam flow pressure control valve to maintain the pressure of thesteam supplied to the steam inlet.
 7. The apparatus of claim 1 furtherincluding: i. a condensate source; ii. means to mix the condensate withsteam from the steam source; and iii. a condensate flow control valve tocontrol the supply of condensate to the mixing means.
 8. The apparatusof claim 7 further including a temperature transmitter disposed tomeasure the temperature of steam supply to the steam inlet forming aclosed loop control system of the condensate flow control valve tocontrol the supply of condensate to the steam supply to the steam inletresponsive to the measured temperature.
 9. Apparatus to heat a bitumenfroth by steam comprising: i. a source of steam; ii. an inline heaterbody forming a bitumen inlet, a steam inlet in communication with thesource of steam and a mixture outlet all in common communication witheach other; iii. a steam pressure flow control valve to control thepressure of steam supply to the steam inlet from the steam source; iv. acondensate source; v. means to mix the condensate with steam from thesteam source; vi. a condensate flow control valve to control the supplyof condensate to the mixing means; vii. a steam flow control valve tocontrol the rate of steam supply to the steam inlet from the steamsource; viii. a baffle disposed across the mixture outlet; and ix. anelongate static mixer body forming a passage therethrough, one end ofthe passage in communication with the mixture outlet, the bodysupporting a plurality of baffles disposed to effect a mixing action ofmaterial flowing through the static mixer.
 10. The apparatus of claim 9wherein the baffles are disposed within the static mixer body to imparta lateral, radial, tangential or circumferential directional componentto a material flow through said passage that changes repeatedly alongthe length of the static mixer passage.
 11. The apparatus of claim 9further including a temperature transmitter disposed to measure thetemperature of material flowing through the passage of the static mixerproximal to the end of the passage remote from the end in communicationwith the mixture outlet forming a closed loop control system with thesteam flow control valve to control the supply of steam to the materialto obtain a target output temperature of the material flow leaving thestatic mixer.
 12. The apparatus of claim 9 further including a pressuretransmitter disposed to measure the pressure of steam supply to thesteam inlet from the steam source forming a closed loop control systemof the steam pressure flow control valve to control the supply of steamto the steam inlet responsive to the measured pressure.
 13. Theapparatus of claim 9 further including a temperature transmitterdisposed to measure the temperature of steam supply to the steam inletforming a closed loop control system of the condensate flow controlvalve to control the supply of condensate to the mixing means responsiveto the measured temperature.
 14. A method to heat a bitumen froth bysteam comprising: i. providing a source of steam; ii. contacting thesteam with a bitumen froth flow within an inline heater body; iii.mixing the steam and bitumen froth flow to obtain a uniform temperatureof the mixture material flow.
 15. The method of claim 14 furtherincluding the step of controlling the rate of steam supply of the steamcontacting the bitumen froth to control the uniform temperature of themixture material obtained in the mixing step.
 16. The method of claim 15further including the steps of: i. measuring the uniform temperature ofthe mixture material flow; and ii. varying the rate of steam supply ofthe steam contacting the bitumen froth flow to obtain a target uniformtemperature of the mixture material flow.
 17. The method of claim 14further including the step of controlling the pressure of the steamsupply of the steam contacting the bitumen froth.
 18. The method ofclaim 17 further including the steps of: i. measuring the controlledpressure of the steam supply; and ii. varying the rate of the steamsupply to obtain a target pressure of the steam contacting the bitumenfroth.
 19. The method of claim 14 further including the step ofproviding a condensate to the steam supply to control the temperaturethe steam contacting the bitumen froth.
 20. The method of claim 19further including the steps of: i. measuring the controlled temperatureof the steam supply contacting the bitumen froth; and ii. varying therate of providing condensate to the steam supply to obtain a targettemperature of the steam contacting the bitumen froth.
 21. A method toheat a bitumen froth by steam comprising: i. providing a source ofsteam; ii. controlling the pressure of the steam; iii. controlling thetemperature of the steam; iv. controlling the rate of supply of thesteam; v. contacting the steam with a bitumen froth flow within aninline heater body; and vi. mixing the steam and bitumen froth flow toobtain a uniform temperature of the mixture material flow.
 22. Themethod of claim 21 further including the steps of: i. measuring theuniform temperature of the mixture material flow; and ii. varying therate of steam supply of the steam contacting the bitumen froth flowresponsive to the measured temperature.
 23. The method of claim 21further including the steps of: i. measuring the controlled pressure ofthe steam supply; and ii. varying the rate of the steam supplyresponsive to the measured pressure.
 24. The method of claim 21 furtherincluding the steps of: i. measuring the controlled temperature of thesteam supply contacting the bitumen froth; and ii. varying the rate ofproviding condensate to the steam supply responsive to the measuredtemperature.